Anchor for marine mooring

Abstract

Anchor for mooring of buoyant marine structures. The anchor comprises an elongated shaft with a mooring line attachment that is rotatable around the full circumference (that is, a full 360 degrees of rotation) of the anchor shaft. The lower end of the shaft comprises nose section, while the upper end comprises a tail section. A plurality of fins are attached to the nose section and tail section, and extend radially outward from the anchor shaft. While the number of fins may vary, one presently preferred embodiment has three fins in each section of the anchor shaft. The anchor is preferably configured (via design of the nose and tail section fin areas, shapes, etc., and the location of the mooring line attachment along the anchor shaft) such that less soil resistance is created on the nose section than on the tail section under the influence of a mooring line load, so that the anchor will rotate slightly about the mooring line attachment point under the applied load while penetrating deeper into the soil underlying the seabed.

1. A seabed penetrating anchor, comprising:
 a) a central elongated shaft having a tail section proximal one end and a nose section proximal another end; 
 b) a plurality of radially outwardly extending fins disposed on said shaft in said tail section; 
 c) a plurality of radially outwardly extending fins disposed on said shaft in said nose section; and 
 d) a rotatable mooring line attachment disposed on said shaft between said tail section and said nose section, wherein said mooring line attachment is rotatable to any point around a circumference of said shaft under the influence of a mooring line force. 
 
   
   
     2. The anchor of  claim 1 , wherein said tail section comprises three fins. 
   
   
     3. The anchor of  claim 2 , wherein said nose section comprises three fins. 
   
   
     4. The anchor of  claim 3 , wherein said rotatable mooring line attachment comprises a collar member at least partially encircling said shaft and longitudinally fixed on said shaft by one or more shoulders on said shaft. 
   
   
     5. The anchor of  claim 4 , wherein said collar member is disposed in a groove on said shaft. 
   
   
     6. The anchor of  claim 4 , wherein said collar member comprises a shackle. 
   
   
     7. The anchor of  claim 4 , wherein said collar member comprises a load ring. 
   
   
     8. The anchor of  claim 1 , wherein at least some of said fins have a profile shape comprising a straight edge angled away from a longitude of said shaft. 
   
   
     9. The anchor of  claim 1 , wherein at least some of said fins have a profile shape comprising a portion of an ellipse. 
   
   
     10. The anchor of  claim 1 , wherein the outer edges of said fins comprise a rectangular edge. 
   
   
     11. The anchor of  claim 1 , wherein the outer edges of said fins comprise a V-shaped edge. 
   
   
     12. The anchor of  claim 1 , wherein the outer edges of said fins comprise a width larger than a thickness of said fins. 
   
   
     13. The anchor of  claim 1 , wherein the end of said shaft comprising said nose section forms a pointed cone, and wherein said fins in said nose section terminate before a base of said cone. 
   
   
     14. The anchor of  claim 1 , wherein said fins in said nose section extend beyond the end of said shaft comprising said nose section. 
   
   
     15. The anchor of  claim 1 , wherein said shaft is hollow. 
   
   
     16. The anchor of  claim 1 , wherein said shaft is solid. 
   
   
     17. The anchor of  claim 1 , wherein an outer diameter of said shaft proximal said nose section is larger than an outer diameter of the remainder of said shaft. 
   
   
     18. The anchor of  claim 1 , wherein said mooring line attachment is longitudinally fixed on said shaft at a location which, when said anchor is subjected to a horizontal force from said mooring line when said anchor is embedded in soil, creates a force tending to rotate said nose section toward said mooring line. 
   
   
     19. The anchor of  claim 1 , further comprising a trailing buoy connected to said anchor by a line, whereby when said anchor is installed by a freefall method said trailing buoy tends to maintain said anchor in a vertical orientation.